“I very recently learned that I have breast cancer. It was detected through a regular mammogram. It’s a little scary, but my prognosis is good and I expect a full recovery,” McCaskill wrote. “I will be in St Louis for the next 3 weeks receiving treatment. During this time my staff will continue to assist Missourians and I will be posting on my Senate website. how I would have voted on any matters that come before the Senate during my absence—which I’ll also enter into the Congressional record. Additionally, I’ll be submitting questions in writing for any missed Senate hearings.”

“Thank you for the honor of serving you in the Senate.”

In 2005, McCaskill opposed a state constitutional amendment to ban same-sex marriage, saying it was unnecessary, but still opposed marriage equality personally. In 2013, she announced she had evolved on the issue and now fully supported marriage equality.

“I have come to the conclusion that our government should not limit the right to marry based on who you love,” McCaskill said when she announced her change of heart. “While churches should never be required to conduct marriages outside of their religious beliefs, neither should the government tell people who they have a right to marry.”

A member of the Armed Services Committee, McCaskill was a co-sponsor of legislation to repeal “Don’t Ask Don’t Tell,” the discriminatory ban on gays in the military.